[Leader] - nonlinear path source for obstacle avoidance

[buckbaskin]

when a nearby obstacle is observed, add in a source with strength based on confidence in the obstacle, etc. This may need to be dynamic.

[buckbaskin]

One interesting variation would be to track the relative location of obstacles, and use that information to dynamically warp the space around the obstacle to locally include obstacles. I like this idea, but it would be pretty complicated.